Lipids

As you read this lecture, you should consider how this information affects
you personally and how the person whose diet you tracked compares to this information...

&nbsp &nbsp The lipids, commonly known as fats &amp oils, are your secondary source of
energy, but also provide the precursors of several important hormones and are key
ingredients in cell membranes.

§ 1. classes of lipids

There are three classes of lipids that are important to Nutrition:
&nbsp triglycerides consist of three fatty acids attached to a glycerol
‘backbone’
&nbsp phospholipids which are triglycerides with two fatty acids and one
phosphorylated fatty acid
&nbsp sterols consist of interconnected carbon ring compounds with
differing side chains

§ 2. Fatty acids

The general chemical formula for fatty acids is
CH3-(CH2)n-COOH, [where n is usually an odd
number between 11 and 17]
which is a hydrocarbon [a chain of Carbon (C) atoms with Hydrogens (H)
attached] with a acid radical (COOH) replacing an H at the terminal end of the
hydrocarbon chain. The acid radical is a Carbon (C) double-bonded to an Oxygen (O)
and single-bonded to a hydroxyl (OH) [I will sometimes use the symbol -(C=O)-OH for -COOH], leaving one unused bond location on the
Carbon [for a valence of ± 1]. Chemists number the Carbons from the acid end
[also called the alpha-end], but nutritionists number the carbons from the opposite
end [called the omega-end because alpha (α) is the first letter of the Greek alphabet,
and omega (Ω) is the last letter of the Greek alphabet]. Some of the characteristics of
the fatty acids are derived from the hydrocarbon properties, so we need to look at
the hydrocarbons as well as at the fatty acids to fully understand the chemistry
involved. The first 4 hydrocarbons (metane, ethane, butane &amp propane) are gases
at room temperature, although butane and propane can be liquified by pressure (as in
butane lighters, and LP gas or liquified propane). The next several are liquids
[gasoline, light machine oil, automotive oil] at room temperature, but at 18 or more
carbons, they are semi-solids [consistency of butter, and lubricating grease]. The
hydrocarbon with 40 to 70 C's is called asphalt. By the way, the ‘octane’ rating
number on gasoline is the percentage of energy released on burning [average of
theoretical and ‘research,’ or controlled burn in a calorimeter] compared to the
8-Carbon hydrocarbon, or Octane]. The following table lists the first 8 hydrocarbons and their
fatty acid equivalents, and you should probably scroll quickly down to the next paragraph,
ignoring the table as if it were intended to amuse me more than it would you.

hydrocarbon

fatty acid

methane

CH4

CH3-COOH

ethane

CH3CH3

CH3CH2-COOH

butane

CH3CH2CH3

CH3(CH2)2-COOH

propane

CH3(CH2)2CH3

CH3(CH2)3-COOH

pentane

CH3(CH2)3CH3

CH3(CH2)4-COOH

hexane

CH3(CH2)4CH3

CH3(CH2)5-COOH

heptane

CH3(CH2)5CH3

CH3(CH2)6-COOH

octane

CH3(CH2)6CH3

CH3(CH2)7-COOH

The hydrocarbons are considered to be “saturated” when they are saturated
with Hydrogens. When they are not saturated there will be at least one double bond
between adjacent Carbons. The effect of double bonding which interests us is to lower
the melting point, so a saturated fatty acid such as
CH3(CH2)13COOH that is semisolid (lard) at room
temperature, would be liquid (corn oil) if it were unsaturated such as
CH3(CH2)5CH=CH(CH2)6COOH
Note: in Chemistry these molecules [hydrocarbons or fatty acids] are either
saturated or unsaturated; there is no distinction between ‘monounsaturated’
and ‘polyunsaturated.’ The term “polyunsaturated” was first used
by an advertising agency hired to promote [if memory serves me well] a well-known
brand of margarine. Other than ‘one or more’ versus ‘zero,’ how
many double bonds is far less important to Nutrition and Wellness than is the location
of the first double bond counting from the omega-end (Ω). The unsaturated oils
are named by the location of the first double bond: omega-3, omega-6, or omega-9.
There may be additional double bonds, but it does not matter to the functioning of the
fatty acids in the Human body. Most Ω-6 plant (or animal) oils also have a double
bond at Ω-9, and the Ω-3 plant (or animal) oils usually have double bonds at
Ω-6 &amp Ω-9. The following chemical formulae illustrate each of the
biologically significant fatty acid types:
&nbsp &nbsp &nbsp &nbsp &nbsp
C#1 , C#2 , C#3 ,
C#4 , C#5 , C#6 ,
C#7 , C#8 , C#9 ,
C#10 , C#11&nbsp (Sat..)
CH3-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-COOH
&nbsp (Ω-9)
CH3-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH=CH-CH2-COOH
&nbsp (Ω-6)
CH3-CH2-CH2-CH2-CH2-CH=CH-CH2-CH=CH-CH2-COOH
&nbsp (Ω-3)
CH3-CH2-CH=CH-CH2-CH=CH-CH2-CH=CH-CH2-COOH
&nbsp The saturated fatty acids, rich in cholesterol, are typically found from
animal sources [“lard”], and are associated with arthrosclerosis… and
heart attacks &amp strokes; the unsaturated fatty acids are from vegetable (&amp
some animals, especially fish) sources [oils], and contribute less to arterial
plaque. However, Grandmother's flaky pie crusts were made with good old pig lard;
pie crusts made with corn oil resemble cardboard [a good grade of cardboard, but
cardboard none-the-less]. There is also an aesthetic difference: imagine, if you
will, a stack of pancakes hot off the griddle [if you're trying to lose weight, you
can imagine a short stack]. Now picture the pat of butter (saturated and Ω-9
fatty acids) melting into the pancakes as the maple syrup runs off the stack and
onto the plate. Now repeat the image, but this time that stack of beautiful
golden-brown pancakes hot off the griddle gives off a wisp of steam as it is placed
in front of you. Anticipating the delicious breakfast to follow, you grab the jar
of corn oil (mostly Ω-9 with some Ω-6's) and pour it onto the pancakes.
Whoa! Instantly soggy and disgusting -
“I'm not going to eat that, let's get Mikey…” So now we had to choose
heart attack or aesthetically pleasing pancakes, with butter melting its saturated
fatty acids into the pancakes. Ah, but we were wrong. It is not the high cholesterol
in saturated animal fats that causes heart attacks. It is the saturated and Ω-9
fatty acids that plaque out best on arterial walls. Ω-6 fatty acids do not plaque
out as much, and Ω-3 fatty acids actually dissolve existing plaque, decreasing
the risk of heart attack.
&nbsp The most heart attack friendly fatty acids (saturated, plus with high
cholesterol) come from red meat, where ‘red’ does not describe the color - pork may
be “other white meat,” but it is the reddest meat in terms of speeding up
that heart attack. White meat, such as chicken, rabbit, some fish [catfish, perch],
are Ω-6 sources with little cholesterol; the heavier plant oils (most famously,
corn) is also Ω-6 with no cholesterol. The best Ω-3 oils are, in order of
decreasing Ω-3 density,
&nbsp &nbsp 1. white fish [again ‘white’ is not a color, but a good source of
Ω-3 oils; the best way to determine if a fish is ‘white’ is if it can be flaked
when cooked properly]. Salmon (with pink flesh) is definitely a white fish. Shellfish
also count as white fish
&nbsp &nbsp 2. Almonds, pecans, &amp other tree nuts
&nbsp &nbsp 3. peanuts, and any non-low fat peanut butter not enriched with
Salmonella [the ‘low fat’ peanut butters I have read the labels on
have reduced the density of Ω-3 oils and replaced them with Ω-6 oils, making
them just as dense in fat, but less healthy]. Sunflower seeds are also a good Ω-3
source
&nbsp &nbsp 4. plant oils: canola (which has a slight buttery flavor), sunflower,
safflower, flaxseed, soybean, olive [olive oil is not the highest in Ω-3 oil, but
has a very effective trade organization promoting it], peanut (especially for frying
potato chips). These are listed here as low density because you should not consume
large quantities of added oils
&nbsp You need to know that Illustration 18.5 (pg 18-6) in Nutrition Now,
5th ed. shows saturated fats, Ω-9 oils (as monounsaturated) and
lumps Ω-6 &amp Ω-3 oils (as polyunsaturated). Therefore, it does not depict
the amounts of Ω-3's and Ω-6's separately. As noted on pg 18-8 in that text,
a 2000 study has suggested that the ratio of Ω-6 to Ω-3 is important, and
should approximate (as a guess, not documented) 4 to 1 or less, but more than 1 to 1.
Unfortunately, information available to consumers of food stuffs about the ratio of
Ω-6 to Ω-3 is largely non-existant.
&nbsp Two specific Ω-3 oils are important to CNS (Central Nervous System = brain
and spinal cord) maintenance and blood clotting control, plus anti-inflammatory function.
These are DHA (docosahexaenoic acid) and EPA (eicosapentaenoic acid). Both are found at
high density in fish oils [except fish liver oil, as in Gramma's cod liver oil]. I think
(but am not sure) that at least DHA is commercially extracted from seaweed for use in
baby formulas. As will be my advice repeatedly on nutrient intake, Food is the
preferred source for nutrients [including Ω-3 oils]; supplements are NOT.
Food comes from plants and animals and have been our nutrient source for well over
1,000,000 years; supplements grow in factories and we simply have not had time (in
generations) to adapt to artificial nutrients.

&nbsp &nbsp Remember our stack of pancakes with butter melting into them,
and syrup flowing off onto the plate? We wanted the nice thin, runny maple syrup
rather than the ‘thickest’ Mrs Butterworth's due to the unacceptably
high corn syrup content of thick syrups [think Karo, 100% corn syrup]. When we
replaced the cholesterol-rich saturated butterfat with Ω-6 corn oil [Crisco],
we ended up with soggy and disgusting pancakes that we didn't want to eat. “Never
fear, Underdog is here,” and so are the dedicated Chemists who provide us with an
endless supply of non-foods for our food supply. We can, with the magic of modern
Chemistry, make perfectly good plant oils look more like butter by hydrogenation
(then adding FD &amp C Yellow no. 5 and Yellow no. 6)! “And what,” you
should be asking, “is hydrogenation?”
Hydrogenation involves breaking one of the bonds in a double bond, then adding 2
Hydrogens. “Partially hydrogenated” means there are fewer double bonds, but
there still remains at least one double bond; “fully hydrogenated” means
that all of the double bonds have been converted to single bonds, and no more
hydrogens can be added - the molecule is saturated. To illustrate, let's start
with an Ω-6 corn oil:
&nbsp naturally occurring Ω-6:
CH3-CH2-CH2-CH2-CH2-CH=CH-CH2-CH=CH-CH2-COOH
&nbsp partially hydrogenated Ω-6 [and Ω-9 for comparison]:
CH3-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH=CH-CH2-COOH
CH3-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH=CH-CH2-COOH
&nbsp fully hydrogenated Ω-6 [and saturated for comparison]:
CH3-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-COOH
CH3-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-COOH
&nbsp Notice the naturally occurring Ω-6 fatty acid is
‘polyunsaturated,’ and is an essential fatty acid because it is a normal
component of cell membranes which are found in high amounts in nerve cells. After
being partially hydrogenated, it is ‘monounsaturated,’ and looks exactly like
an Ω-9 fatty acid, so should be expected not to contribute to nerve cell
membranes, but to plaque out on arterial walls, cause blockages and heart attacks. As
a fully hydrogenated Ω-6 fatty acid it is now saturated, and looks exactly
like a saturated fatty acid, so should be expected not to be an essential fatty acid
but to be fully as effective at producing heart attacks and strokes as was the
butterfat we were trying to avoid by using margarine as a butter substitute!
If that were the entire story, we could say that if you like the flavor of butter,
eat butter; if you prefer the flavor of margarine, eat margarine; if you don't want a
heart attack, eat dry toast for the rest of your life. “And now, the rest of the
story…” the long chain of the fatty acids is not straight as drawn in
2-dimensions. In 3-d [with your 3-d goggles] the molecule zigs and zags. At each
C - C bond the 2nd C could zig to the right or zag to the left. Yet in
biologically produced fatty acids, the bonds tend to zag to the left, making them
levo-rotary, or left-handed and politically correct
[called cis-fats]. But, when made in the laboratories of
our friendly, dedicated Chemists out to improve our lives, these molecules both zig
and zag, so only about half are good levo-rotary (cis-fat) molecules, while the other
half have gone over to the dark side and are dextro-rotary, or right-handed [called
trans-fats] which is evil. [See, all that discrimination
against left-handedness is driven by right-handed Jedi on the dark side of the force
(if you are right-handed disregard this sentence)]. Dextro-rotary (trans-fat) is not
good because all your enzymes are designed to deal with levo-rotary molecules. Under
the Lock &amp Key Hypothesis, enzymes do not “fit” dextro-rotary molecules,
and do not process them at all. The poor, neglected dextro-rotary trans-fats, shunned
by the levo-rotary enzymes, are left to roam not the streets but the arteries where
they join the street gang Plaque. Translated to English, this means that persons who
eat butter are more likely to have heart attacks than do people who don't eat butter.
However, persons who do eat margarine are more likely to have heart attacks
than are people who eat butter. So now we have: if you like the flavor of real butter
(from happy cows, the California type), eat butter. If you really want to have that
heart attack soon and get it over with, eat more trans fats. If you would prefer to
wait for your heart attack (perhaps until after you die from other causes), eat dry
toast for the rest of your life. Or eat butter, but put creamy peanut butter on your
hot toast without butter. The peanut butter melts nicely into the toast, tastes good,
and counter-acts the negative effects of the butter. [Our friendly, dedicated Chemists
are not really evil, and are working on methods to produce levo-rotary hydrogenated
fatty acids. Crisco announced in 2007 that they had developed a new version of
their shortening with only 0.49 grams trans-fats, so it had to be labeled 'zero grams
trans-fat,' and that they wanted their customers to know that it is 0.49 g more than
zero]
&nbsp The whole dextro-rotary versus levo-rotary thing was first discovered with
synthetic versions of Insulin and Thyroxin. After observing that it took twice the
dose rate of the synthetic insulin or thyroxin to get the same effect as the natural
molecules, the chemists re-examined their molecules and discovered rotary-ness. They
then altered the manufacturing process to produce mostly (if not entirely) the
levo-rotary molecules.

§ 3. Triglycerides (fats & oils)

Triglycerides are three fatty acids attached to a glycerol. Gylcerol is an alcohol
with three -OH groups:

CH2OH
&nbsp|
CHOH
&nbsp|
CH2OH

A fatty acid can be dehydrated onto this molecule by removing the -H from the -OH
on the -COOH (1'-C end of the fatty acid and the -OH from the 1'-C end of the
glycerol:

CH2OH &nbsp HOOC-(CH2)n-CH3&nbsp|
CHOH
&nbsp|
CH2OH

yielding a monoglyceride:

CH2-O-(C=O)-(CH2)n-CH3&nbsp|
CHOH
&nbsp|
CH2OH

repeating this on the 2'-C of the monoglyceride yields a diglyceride;
and then again on the 3'-C of the diglyceride to make the triglyceride:

&nbsp You may be aware that oil and water don't mix. If you doubt this, try this
experiment at home: mix roughly equal amounts of wine vinegar (a solution of acetic
acid in water) with extra virgin olive oil, and add some Italian seasoning. Shake
vigorously, and spread over a bed of mixed lettuce varieties. Pass the container of
the vinegar &amp oil to the person on your left, and observe whether or not the
mixture has separated. Then enjoy your salad. Now that you've had some salad, we
can note that the hydrocarbon (omega end of the fatty acid) is not soluble in water
(and is oil soluble), but the acid group (-COOH) on the alpha-end of the fatty acid
is water soluble. The chemical term for a molecule that is water soluble on
one end and oil soluble on the other is detergent. Dish
detergent, such as Dawn, works by dissolving the oil soluble ends of the
detergent molecules in the grease on the dishes, leaving the water soluble ends
sticking out as a surface (of the grease globule) that is water soluble, so the
entire grease globule dissolves in the dish water.
&nbsp So a fatty acid is a detergent, but when dehydrated onto a glycerol, the
water soluble end is covered by the glycerol, and the water soluble alcohol groups
(-OH) on the glycerol are covered by the fatty acid. As a triglyceride, the entire
structure is no longer water soluble. Another name for triglyceride is fat. Fatty acids are slightly soluble in water and can be
transported in the blood stream; while fats are completely insoluble in water and
can no longer be picked up by the blood stream and transported. This makes fats an
excellent long term storage of rather stable, energy-dense molecules.
If your long-lost ancestors were Cro-Magnons [which they were (Cro-Magnons were
‘Modern Humans’)] who happen to live closer to the Pleistocene glaciers
than most other Cro-Magnons [like the ones in southern France making cave paintings
(a.k.a. graffiti)], they would have needed some means of storing large quantities of
energy-dense material to support Life during the long winters (similar to the famous
Winter of 2008-2009 in Northern Indiana, between Donaldson and Lake Michigan. You may
remember this particular winter if you were anywhere near Donaldson, IN, that
season).
&nbsp Unfortunately, since the oil-soluable ends of fatty acids (especially the
saturated, Ω-9 &amp trans-fat ones) can dissolve in the cell membranes of the
lining of your arteries, then other saturated, Ω-9 &amp trans-fat fatty acid
molecules can dissolve in the oil-soluable ends of these fatty acids to produce
long-term fatty acid storage as arterial plaque [sufficiently long-term to be a
‘Life Time supply’, due to the premature death due to heart attack]. The
Ω-3 fatty acids also dissolve in the plaque, but remain dissolved in the fluids
(water) in the blood stream,so the ‘stored’ fatty acids in plaque are
returned to the blood stream to be removed by the liver and kidneys.

§ 4. dietary sources of lipids

Saturated fats and Ω-9 fatty acids come primarily from animal sources [including
dairy], which are also the best dietary sources of cholesterol [plants, in general,
contain little to no cholesterol]. From a nutrition point of view, the
‘redness’ of meat refers to the cholesterol-density, and saturated fat
density. The ‘white’ meats have low density of cholesterol and saturated
fats, but remain Ω-9 fatty acid dense. All fish are white-meat sources, but some
are classified as ‘white-fish.’ The best way to determine if a fish is a
‘white fish,’ is to cook it properly [relatively low heat, and cooked until
it is just thoroughly cooked], then attempt to flake it [flaking a fish involves
placing your fork along the side-line on the fish and pulling toward the belly (of the
fish) with pressure. If it is a white fish, the flesh will come off as flakes; if it is
not a white fish, the flesh will come off as lumps]. Those fish with a strong oily smell
are probably not white fish. Over-cooking almost any animal will dehydrate the flesh
making it tough, and destroy both the flavor and most of the nutrient value. Under
cooking red meat will not kill the Botulinum bacteria; while under cooking
white meats does not kill the Salmonella bacteria. Botulinum produces
a powerful toxin [called Botox, for BOtulinum
TOXins. These toxins cause muscle paralysis; death occurs due to the paralysis
of heart muscle. This is clearly why cosmetic Botox injections make such good sense
-who wants to be a corpse with wrinkles on their face? [Hint: a good mortician can get
rid of those ugly wrinkles without killing you; since you'll already be dead by the
time of your appointment].
Salmonella toxins tend to produce moderate to severe gastric symptoms
(diarrhea, cramping, projectile vomiting). Although they can kill you, the death is
not as abrupt as the cardiac arrest associated with botulism; and death usually
results from severe dehydration. Neither botulism nor salmonella poisoning are
pleasant experiences. I recommend avoiding both.
&nbsp The dietary sources of Ω-6 &amp Ω-3 fatty acids include white fish
[the kind that flake] and plant sources. Not only are the white fish the highest
density source of Ω-3 fatty acids, they are, in my opinion, the best tasting
fish. White fish are cold water predators: salmon and trout (a genus in the salmon
family), pike, flounder, talipia, mahi-mahi, whitefish, sole, etc. If you don't like
fish as part of your food supply, you should try to learn to like them. They will
make you live longer, and with fewer signs of aging; they are brain food in that they
reduce the risk of non-Alzheimer's age-related dementia. Your second choice for
Ω-3 fatty acids is tree nuts &amp peanuts. A good blend of Ω-6 and Ω-3 fatty
acids can be found in dark, leafy green vegetables (dark green lettuce varieties,
Brussel sprouts [yes, it's cabbage]) and cruciferous vegetables (cauliflower,
broccoli) and whole grain (non-bleached, non-enriched) grains; but you still need
fish and nuts to boost the Ω-3 fatty acid intake.
The term “reduced fat” on the front of food packaging should not be
taken to mean healthier. Most reduced fat products also come with increased carbs;
just as reduced carb foods also come with increased fats. Many ‘reduced fat’
products, according to their nutrition facts label, seem to substitute less healthy
fats for the naturally occurring Ω-3 &amp Ω-6 oils.

§ 5. nutrient values of lipids

Fat constitutes our primary form of long term energy storage, which is
intended to be released only in an emergency, such as cave-man winter when food was
scarce at best. Modern Humans release long term fat storage in response to prolonged
illness, since winter never comes (in that we will probably never see a period of a
few to several months without a food supply). Curiously [for most people], the
trigger for increased fat deposition is reduced carbohydrate density in the food
intake [naturally occurring food supply reaches its maximum carbohydrate density in
late summer]. As a result, many reduced carb weight management programs cause
fat deposition rather than the desired reduction in body measurement (waist
size for example). On the other hand, one of the triggers for satiety (cessation of
desire to eat) is increased serum fatty acids; so many low fat weight management
programs fail due the failure to achieve satiety, leading to continual munching
[of mostly high carb density snack ‘foods’]. A couple of side effects of
maintaining adequate adipose deposits are (1) insulation to assist in maintaining
body temperature, and (2) “padding” which protects soft tissues including
a number of rather key vital organs.
&nbsp The essential fatty acids are involved in cell reproduction (forming cell
membranes for the newly forming cells) and therefore healthy skin, adequate red blood
cells, sperm production for Human reproduction, and maintaining healthy nervous
tissues (particularly in the Brain &amp CNS). Dietary fatty acids assist in absorbing
fat soluble vitamins. Some (Ω-3 &amp Ω-6) fatty acids combine in the blood
serum with proteins forming lipoproteins. The lipoproteins are either high density,
HDLs (the good guys ["H" for Healthy]) or low density, or LDLs
(the bad guys ["L" for Lousy]. HDL's seem to function as anti-oxidants and as
anti-inflammatory agents; LDL's are now believed to be oxidants, promoting aging and
declining health.
You get your cholesterol from the frankfurters you ate and from your Uncle Frank.
All Humans can produce cholesterol [from Ω-6 fatty acids, mostly] at a rate which
is determined by your family tree (Genetics), hence ‘Uncle Frank.’ However, you
must understand that you need cholesterol both as an ingredient in cell
membranes and as a precursor to the steroidal hormones, notably estrogen,
testoserone, and human growth hormone. Unfortunately, the best cholesterol producers
can make only enough for normal production of steroidal hormones and for repair of
damage to skin tissue (blood clot &amp scar formation). During growth phases
[sometimes called childhood] additional cholesterol is required from dietary sources.
The Yuppies (1980's) mistakenly thought that if low cholesterol diets were good for
preventing heart attacks in 40-ish to 40-somethings people, it should be much better
to start younger, say 6 to 8 year olds. They successfully produced a population of
stunted young adults, from which we concluded that dietary cholesterol is
required during growth periods. It has been suggested by relible sources
that the slowing of the healing processes in the elderly are due to a decline in
cholesterol production, again requiring additional dietary cholesterol in the over 40
population. And, we now know that serum cholesterol has absolutely no predictive
value in heart attack risk (although persons with elevated cholesterol have diets
which favor the production of LDL's, which do have high predictive value for heart
attack risk).
Side effects associated with fats and oils are pleasant flavor and texture in
foods. A negative side effect is that fats spoil more rapidly than most other
nutrients, and become rancid giving the food an unpleasant aroma [this is not
entirely negative, because most people will discard food as soon as the fats in it
have become rancid, and before the proteins have spoiled enough to cause serious
food poisoning].